Related papers: Sgr dSph: a bridge between Dwarf Galaxies and DLAs…
We derive homogeneous abundances of Fe, O, Na and alpha-elements from high resolution FLAMES spectra for 76 red giant stars in NGC 6715 (M 54) and for 25 red giants in the surrounding nucleus of the Sagittarius (Sgr) dwarf galaxy. Our main…
We investigate the orbital motions of dwarf spheroidal galaxies (dSphs) in the halo of the Milky Way (MW) to understand their possible effects on the diversity of the star formation histories seen in these MW satellites. In this work, we…
In this paper we present the first results of the analysis of intermediate resolution ($\Delta\lambda \sim 3.5 \AA$) spectra of giants of the Sagittarius dwarf galaxy acquired using the ESO NTT telescope. From the deep CCD photometry of…
We report the discovery of a significant old population in the dwarf spheroidal (dSph) galaxy Leo I as a result of a wide-area search with the ESO New Technology Telescope. Studies of the stellar content of Local Group dwarf galaxies have…
We estimate the optical depth, time-scale distribution and fraction of microlensing events originating from sources in the Sagittarius dwarf galaxy (Sgr) lensed by deflectors in the Milky Way. These events have a time-scale longer by a…
It is now established that several of the Local Group dwarf Spheroidal galaxies (dSphs) have large mass-to-light ratios. We consider the possibility that the dark matter in the halos of dSphs is composed of massive black holes with masses…
We discuss the role that dwarf galaxies may have played in the formation of the Galactic halo (Halo) using RR Lyrae stars (RRL) as tracers of their ancient stellar component. The comparison is performed using two observables (periods,…
The most metal-poor stars provide valuable insights into the early chemical enrichment history of a system, carrying the chemical imprints of the first generations of supernovae. The most metal-poor region of the Sagittarius dwarf galaxy…
We have used UVES on VLT-UT2 to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies: Sculptor, Fornax, Carina and Leo I. We measure the abundance variations of numerous elements in these low…
We investigate the effects of a massive ($\gtrsim4\times10^{10}M_\odot$) Sagittarius dwarf spheroidal galaxy (Sgr) on stellar streams using test particle simulations in a realistic Milky Way potential. We find that Sgr can easily disrupt…
Based on the observed paucity of the dwarf spheroidal (dSph) satellites of the Milky Way at small Galactocentric distances, we put forward the hypothesis that subsequent to the formation of the Milky Way and its satellites, those dSphs that…
The existence of dwarf spheroidal galaxies with high internal velocity dispersions orbiting in the Milky Way raises questions about their dark matter content and lifetime. In this paper, we present an alternative solution to the dark matter…
Globular clusters (GCs) are important tools to rebuild the accretion history of a galaxy. There are newly discovered GCs in the Sagittarius (Sgr) dwarf galaxy, that can be used as probes of the accretion event onto the Milky Way (MW). Our…
The Milky Way ultra-faint dwarf galaxies (UFDs) contain some of the oldest, most metal-poor stars in the Universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], and mean [alpha/Fe], abundance ratios for 61 individual red giant branch stars…
We present uniformly measured star formation histories (SFHs) of 60 nearby (D~4Mpc) dwarf galaxies based on CMDs of resolved stellar populations from images taken with HST as part of the ACS Nearby Galaxy Survey Treasury program (ANGST).…
The discovery of the Sgr dwarf galaxy (Ibata, Gilmore, Irwin 1994) shows that the Galactic halo contains large clumps which are not full viralized. Stars in such a clump can lense a background extragalactic source. I use parameters of Sgr…
We present deep $BVI$ observations of the dwarf irregular galaxy UKS1927-177 in Sagittarius. Statistically cleaned $V$, $(B-I)$ CMDs clearly display the key evolutionary features in this galaxy. Previously detected C stars are located in…
We present spectroscopic observations from the {\it Spitzer Space Telescope} of six carbon-rich AGB stars in the Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph) and two foreground Galactic carbon stars. The band strengths of the observed…
We use a numerical simulation of a loose group containing a Milky Way halo to probe that in the hierarchical universe the Magellanic Clouds and some dSphs have been accreted into the Milky Way halo from a late infalling group of dwarfs. Our…
The Sagittarius dwarf spheroidal (Sgr) is a dissolving galaxy being tidally disrupted by the Milky Way (MW). Its stellar stream still poses serious modelling challenges, which hinders our ability to use it effectively as a probe of the MW…